Microbiological contamination of an oil or natural gas environment can lead to degradation of hydrocarbons, and increased sulfur content and viscosity. These changes adversely impact extraction and processing equipment by causing corrosion and production of hydrogen sulfide and other undesirable substances. Antimicrobial additives have been used to control the growth of microorganisms in such environments. While glutaraldehyde, Bronopol and THTP have been used extensively for controlling these organisms in subterranean formations, only Bronopol and THTP have been available in solid rod form to allow well delivery modes.
Solid glutaraldehyde derived by forming a hemiacetal derivative with sucrose is described in U.S. Pat. No. 5,158,778. While the existing solid glutaraldehyde composition is an effective antimicrobial, the composition is a true glass which, though hard and brittle, “flows” like an extremely viscous liquid. The glass transition temperature of the solid glutaraldehyde is about 45° C., which is less than desirable for use in many high temperature environments such as oil fields. More specifically, such solid glutaraldehyde will not maintain it shape when exposed to temperatures of about 50° C. for more than several hours. Since a ball valve access port on a well has an internal diameter ranging from 1 to 1-¼ inch, even minor deforming of the rod can prevent insertion through the valve. Additionally, when the rods are exposed to such temperatures, they tend to fuse to one another again prohibiting insertion through the valve. When a conventional rod is inserted into the ball valve, it typically falls one to two miles down the annulus cavity of the well. If it hits the sides of the annulus, and it is fragile, it will form a surface coating resulting in loss of material and requiring a costly water rinse of the annulus It would therefore be useful to provide solid glutaraldehyde compositions of greater strength to better withstand normal handling without breakage, and to resist deformation or fusing of rods so that the rods can fall through the annulus cavity of a well with minimal or no loss of material from collisions with the annulus surface.